Note 1 - Description of Business and Summary of Significant Accounting Policies (Details Textual) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Foreign Currency Transaction Gain (Loss), before Tax, Total	$ (44)	$ (2,168)
Intangible Assets, Percent of Total Assets	11.90%	14.50%
Excessive Dividend Rate of Class B Over Class A	5.00%
Excessive Undistributed Earnings Allocation Rate of Class B Over Class A	5.00%
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	0
Research and Development Expense, Total	$ 21,891	$ 23,611
Maximum [Member]
Foreign Currency Transaction Gain (Loss), before Tax, Total	$ (100)
Standard Product Warranty, Period (Year)	3 years
Finite-Lived Intangible Asset, Useful Life (Year)	16 years
Maximum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	33 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	14 years
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	1 year
Minimum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	1 year
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	2 years